An improved closed cranial window technique for investigation of blood-brain barrier function and cerebral vasomotor control in the rat.
A modification of the closed cranial window technique for small laboratory animals is presented. The method facilitates investigation of blood-brain barrier permeability in association with studies of the cerebrovascular response under normal and pathological conditions. Following trephination and preparation of the pia-arachnoid surface, the skull defect is closed again by sealing a cover glass onto a wall of dental cement surrounding the cranial window. The intracranial pressure can then be studied and experimentally manipulated. Care is taken to maintain normal blood-brain barrier function to a small barrier indicator (Na(+)-fluorescein, MW: 376). This is accomplished by opening the skull and dura mater under a column of paraffin oil to avoid exposure of brain tissue to atmospheric pressure. Reactivity of the cerebral surface vessels was assessed during hypercapnia at an arterial PaCO2 of 50.8 +/- 1.1 mm Hg. It was found that small arterioles of 20-50 microns phi had a significantly larger CO2-response than large arterioles of 50-100 microns phi. Pial venules did not respond at all. Superfusion of the cranial window preparation at a rate of 5 ml/h with buffered artificial CSF was tolerated for hours. No alterations of arteriolar or venular diameters nor opening of the blood-brain barrier to Na(+)-fluorescein was observed. These technical modifications enable us to employ a closed cranial window model in small laboratory animals for studies of cerebral microcirculation and blood-brain barrier function under normal as well as under pathological conditions related to brain damage.
Kawamura
S
S
Institute for Surgical Research, Ludwig-Maximilians-University, Klinikum Grosshadern, München, FRG.
Schürer
L
L
Goetz
A
A
Kempski
O
O
Schmucker
B
B
Baethmann
A
A
D000818:Animals; D001812:Blood-Brain Barrier; D002560:Cerebrovascular Circulation; D006935:Hypercapnia / Q000503:physiopathology; D007427:Intracranial Pressure; D008297:Male; D008833:Microcirculation; D010841:Pia Mater / Q000098:blood supply; D051381:Rats; D011919:Rats, Inbred Strains; D012884:Skin Window Technique; D014666:Vasomotor System